JP2015041437A - Lighting device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make luminance unevenness and chromaticity unevenness less likely to occur on a display panel.SOLUTION: A Lighting device includes: a substrate 22 on which LEDs are mounted; and lenses, each of which is disposed facing the LED and increases a light distribution angle of light emitted from the LED. Each lens includes multiple legs that are bonded to the substrate 22 by an adhesive 24. A contact surface 25 of each leg part, which contacts with the substrate 22, is entirely curved into a protruding shape.

Description

  The present invention relates to a lighting device and a display device, and more particularly to a lens structure that widens a light distribution angle of light emitted from an LED (Light Emitting Diode).

  2. Description of the Related Art Conventionally, in a display device such as a liquid crystal display device, a direct type backlight that irradiates light to a display panel has been used (for example, see Patent Document 1). For the backlight, an LED and a lens that widens the light distribution angle of light emitted from the LED are used, but the positional relationship between the LED and the lens affects the optical characteristics of the backlight. For this reason, it is necessary to position the lens so that the positional relationship between the LED and the lens is as designed.

  The lens is adhered to the substrate on which the LED is mounted with an adhesive. For example, the mounter obtains the center of the lens from the outer shape of the lens by image processing, obtains the mounting position of the lens from the position of the recognition mark provided on the substrate, and mounts the lens at the obtained mounting position. Mounted on the board.

JP 2012-204025 A

  However, due to the influence of the adhesive, the lens may not come into contact with the substrate and may float from the substrate. For this reason, the light distribution angle of the light emitted from the LED does not coincide with the design value, and there is a problem that when the light is irradiated on the display panel, luminance unevenness and chromaticity unevenness occur in the display panel.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an illumination device and a display device that are less likely to cause luminance unevenness and chromaticity unevenness in a display panel.

  In order to achieve the above object, a lighting device according to one embodiment of the present invention includes a substrate on which an LED (Light Emitting Diode) is mounted, a light distribution that is disposed to face the LED, and is emitted from the LED. A lens that widens the corners, and the lens has a plurality of legs that are bonded to the substrate by an adhesive, and the contact surface of each leg with the substrate is curved in a generally convex shape. .

  According to this configuration, since the contact surface of the leg portion is curved in a convex shape, the adhesive can be easily poured to the side of the leg portion when the leg portion of the lens is pressed against the substrate. Thereby, the leg part of a lens and a board | substrate can be made to contact reliably, and a lens can be positioned so that the positional relationship of LED and a lens may become a design value. Therefore, when the lighting device is used as a backlight of the display device, luminance unevenness and chromaticity unevenness are less likely to occur on the display panel.

  For example, the shape of the contact surface of each leg may be a spherical crown shape.

  According to this structure, it becomes easy to make the leg part of a lens contact a board | substrate with a point. Thereby, the lens can be positioned so that the positional relationship between the LED and the lens is as designed. Therefore, when the lighting device is used as a backlight of the display device, luminance unevenness and chromaticity unevenness hardly occur on the display panel.

  Further, the contact surface of each leg may have a groove.

  According to this configuration, when the leg portion of the lens is pressed against the substrate, the adhesive can easily flow along the groove portion to the side of the leg portion.

  Further, the contact surface of each leg may have the groove extending radially from the center of the contact surface.

  According to this configuration, when the leg portion of the lens is pressed against the substrate, the adhesive can easily flow from the center of the leg portion along the groove to the side of the leg portion.

  The shape of the side surface of each leg may be an uneven shape.

  According to this configuration, the surface area of the side surface of the leg portion of the lens can be increased. Therefore, the shear strength generated between the lens leg and the adhesive can be increased as compared with the case where the side surface of the lens leg is not uneven. Thereby, it can prevent that a lens peels from a board | substrate.

  For example, the side surfaces of the respective leg portions may be subjected to embossing.

  According to this configuration, the surface area of the side surface of the lens leg can be increased by a simple manufacturing method.

  A display device according to another embodiment of the present invention includes a display panel and the above-described lighting device that irradiates the display panel with light.

  According to this structure, the effect | action and effect similar to the above-mentioned illuminating device can be show | played.

  ADVANTAGE OF THE INVENTION According to this invention, the illuminating device and display apparatus which make it hard to produce a brightness | luminance nonuniformity and chromaticity nonuniformity on a display panel can be provided.

It is an external view of the liquid crystal display which is an example of a display apparatus. It is a disassembled perspective view of the liquid crystal display shown to FIG. 1A. It is the figure which expanded the periphery of the backlight unit. It is the sectional view on the AA line of FIG. 3B is an enlarged view of the leg portion shown in FIG. 3A. FIG. It is an expansion perspective view of a leg part. It is the figure which looked at the lens shown to FIG. 3A from the back surface side (board | substrate side). It is a figure for demonstrating the example of installation of a lens in case the contact surface of each leg part is planar. It is a figure for demonstrating the example of installation of a lens in case the contact surface of each leg part is planar. 3B is an enlarged view of the leg portion shown in FIG. 3A. FIG. It is an expansion perspective view of a leg part. 3B is an enlarged view of the leg portion shown in FIG. 3A. FIG. It is an expansion perspective view of the leg part of a lens. It is a front view of a leg part. It is a right view of a leg part. It is a perspective view of a leg part. It is another front view of a leg part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present invention. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims are described as arbitrary constituent elements.

  Each figure is a schematic diagram and is not necessarily illustrated strictly. Moreover, in each figure, the same code | symbol is attached | subjected to the substantially same structure, The overlapping description is abbreviate | omitted or simplified.

(Embodiment 1)
The display device according to Embodiment 1 will be described with reference to the drawings.

[1-1. Overall configuration of liquid crystal display (display device)]
First, the overall configuration of the display device will be described with reference to FIGS. 1A and 1B. FIG. 1A is an external view of a liquid crystal display 10 which is an example of a display device. FIG. 1B is an exploded perspective view of the liquid crystal display 10 shown in FIG. 1A.

  The liquid crystal display 10 includes a housing 18, and the housing 18 is configured by combining the front cabinet 11 and the rear frame 17 with each other.

  The front cabinet 11 is configured in a frame shape and covers an outer peripheral portion of a liquid crystal cell 13 (which constitutes a display panel) described later. The front cabinet 11 is made of, for example, resin.

  The rear frame 17 is disposed so as to cover the back side of the liquid crystal cell 13.

[1-2. Internal structure of liquid crystal display (display device)]
A bezel 12, a liquid crystal cell 13, a cell guide 14, an optical sheet 15, a reflection sheet 16, and a backlight unit 19 are disposed inside the housing 18.

  The bezel 12 is disposed on the surface side of the cell guide 14 (that is, the side on which the liquid crystal cell 13 is disposed) and covers the outer peripheral portion on the front side of the liquid crystal cell 13.

  The liquid crystal cell 13 is configured in a rectangular panel shape. The outer periphery of the liquid crystal cell 13 is supported by a frame-shaped cell guide 14. An image is displayed on the liquid crystal cell 13 by irradiating the back surface of the liquid crystal cell 13 with light from the backlight unit 19.

  The optical sheet 15 is composed of a plurality of members such as a diffusion plate. For example, the optical sheet 15 has a function of diffusing light from the backlight unit 19.

  The reflection sheet 16 is disposed so as to cover the inner surface of the rear frame 17 (that is, the surface on which the liquid crystal cell 13 is disposed). The reflection sheet 16 has a function of reflecting light from the backlight unit 19 toward the back surface of the liquid crystal cell 13.

  The backlight unit 19 is a direct-type illumination device, and irradiates light toward the back surface of the liquid crystal cell 13. The backlight unit 19 includes one or more LED bars 20 (constituting a lighting device).

  FIG. 2 is an enlarged view of the periphery of the backlight unit 19. The backlight unit 19 includes, for example, six LED bars 20. However, the number of LED bars 20 is not limited to this. The LED bar 20 includes a substrate 22 and a plurality of LED units 28 mounted on the substrate 22. The board | substrate 22 is comprised by the elongate plate shape. The plurality of LED units 28 are arranged in a line and at intervals in the longitudinal direction of the substrate 22. The board | substrate 22 is attached to the inner surface of the rear frame 17 with the double-sided tape (not shown) which has heat conductivity. The substrate 22 is made of a metal having high thermal conductivity, such as aluminum.

[2. Configuration of LED bar (lighting device)]
3A is a cross-sectional view taken along line AA in FIG. FIG. 3B is an enlarged view of the leg 21a shown in FIG. 3A. FIG. 3C is an enlarged perspective view of the leg 21a. FIG. 4 is a view of the lens 21 shown in FIG. 3A as viewed from the back side (substrate 22 side).

  As shown in FIG. 3A, each of the plurality of LED units 28 arranged on the LED bar 20 includes an LED 23 and a lens 21. The LED 23 is mounted on the substrate 22, and the lens 21 is disposed to face the LED 23. The lens 21 serves to widen the light distribution angle of the light emitted from the LED 23. As shown in FIG. 4, the lens 21 is formed with four leg portions 21 a to 21 d on the periphery of the back surface of the lens 21. The four leg portions 21 a to 21 d are bonded to the substrate 22 with an adhesive 24. In addition, in FIG. 3A, illustration of the leg part 21b and the leg part 21d is abbreviate | omitted. Further, the number of the leg portions of the lens 21 is not limited to four and may be three or more.

  As shown in FIGS. 3B and 3C, the contact surface 25 of the leg 21a is curved in a convex shape as a whole. Specifically, the contact surface 25 has a circular shape, the peripheral portion of the contact surface 25 has a flat shape, and the inner shape of the peripheral portion has a spherical crown shape. The contact surfaces of the other leg portions 21 b to 21 d have the same shape as the contact surface 25. Note that the term “convexly curved as a whole” ideally means that 90% or more of the contact surface 25 is curved in a convex shape.

  The lens 21 is fixed to the substrate 22 as follows. That is, the adhesive 24 is applied in advance to the positions where the leg portions 21a to 21d on the substrate 22 come into contact. The mounter fixes the lens 21 to the substrate 22 by pressing the contact surfaces 25 of the leg portions 21a to 21d of the lens 21 against the substrate 22 to which the adhesive 24 is applied.

  The contact surfaces 25 of the leg portions 21a to 21d are curved in a convex shape. Therefore, as shown in FIG. 3B, when the leg 21a of the lens 21 is pressed against the substrate 22, the tip of the contact surface 25 first comes into contact with the adhesive 24, and the contact surface 25 causes the adhesive 24 to pass through the leg 21a. The contact surface 25 is pressed against the substrate 22 while being pushed to the side (in the direction of the arrow). That is, it becomes easy to flow the adhesive 24 to the side of the leg portion 21a (in the direction of the arrow). Similarly, it becomes easy to flow the adhesive 24 to the side of each leg part also about the other leg parts 21b-21d. Thereby, each leg part of the lens 21 and the board | substrate 22 can be made to contact reliably. In particular, since the shape of the contact surface 25 of the leg portions 21a to 21d is a spherical crown shape, each leg portion is easily brought into contact with the substrate 22 at a point. Thereby, the lens 21 can be positioned so that the positional relationship between the LED 23 and the lens 21 is as designed. Therefore, when the LED bar 20 is used as the backlight of the liquid crystal display 10, luminance unevenness and chromaticity unevenness are hardly caused in the liquid crystal cell 13.

[3. Comparison configuration]
On the other hand, the case where the contact surface of each leg part is planar is demonstrated. 5A and 5B are diagrams for explaining an installation example of the lens 21 when the contact surface of each leg portion is planar. When the contact surface is flat, when the mounter presses the leg portions 21a to 21d of the lens 21 against the substrate 22 coated with the adhesive 24, the contact surface and the adhesive 24 start to contact each other. It is difficult for the adhesive 24 to flow to the side of each leg because the contact is made from the surface. For this reason, as shown to FIG. 5A, the contact surface of each leg part cannot be made to contact the board | substrate 22, and it may be fixed in the state which floated from the board | substrate 22. In this case, the distance d2 from the substrate 22 to the tip of the lens 21 becomes larger than the distance d1 determined by the design value. As described above, the positioning of the lens 21 cannot be performed accurately, and uneven luminance and uneven chromaticity occur in the liquid crystal cell 13. Further, as shown in FIG. 5B, the leg portion 21 c contacts the substrate 22, but may be fixed in a state where the leg portion 21 a is lifted from the substrate 22. In this case, the optical axis 21m of the lens 21 is inclined with respect to the optical axis 21n determined by the design value. For this reason, the positioning of the lens 21 cannot be performed accurately, and uneven brightness and uneven chromaticity occur in the liquid crystal cell 13.

[4. effect]
As described above, according to the first embodiment, the lens 21 can be reliably brought into contact with the substrate 22. For this reason, luminance unevenness and chromaticity unevenness can be made difficult to occur in the liquid crystal cell 13.

(Modification of Embodiment 1)
In the first embodiment, the peripheral portion of the contact surface 25 of each leg portion of the lens 21 has a partially flat portion, but the entire contact surface 25 may be curved. FIG. 6A is an enlarged view of the leg 21a shown in FIG. 3A. FIG. 6B is an enlarged perspective view of the leg portion 21a. The shape of the leg portions 21b to 21d is the same.

  As shown in these drawings, the entire contact surface 25 may be curved in a convex shape. Specifically, the entire contact surface 25 may have a spherical crown shape.

(Embodiment 2)
In Embodiment 1, the contact surface 25 of each leg portion of the lens 21 has a spherical crown shape. In the second embodiment, the shape of the side surface of each leg is an uneven shape.

  FIG. 7 is an enlarged view of the leg 21a shown in FIG. 3A. As shown in FIG. 7, the shape of the side surface 26 of the leg 21a is an uneven shape. Specifically, the side surface 26 is subjected to a textured process. The shapes of the side surfaces 26 of the leg portions 21b to 21d are also uneven.

  According to this configuration, the surface area of the side surface 26 of the leg portion of the lens 21 can be increased. Therefore, the shear strength generated between the leg portion of the lens 21 and the adhesive 24 can be increased as compared with the case where the side surface of the leg portion of the lens is not uneven. Thereby, it can prevent that the lens 21 peels from the board | substrate 22. FIG. In addition, by subjecting the side surface 26 to a texture, the surface area of the side surface 26 can be increased by a simple manufacturing method.

  In addition, the shape of the side surface 26 is not limited to what is illustrated, and may be any shape as long as it is an uneven shape.

(Embodiment 3)
In Embodiment 1, the contact surface 25 of each leg portion of the lens 21 has a spherical crown shape. In Embodiment 3, the contact surface 25 has a spherical crown shape and has a groove.

  FIG. 8 is an enlarged perspective view of the leg 21 a of the lens 21. The shape of the leg portions 21b to 21d is the same. A groove portion 27 is provided on the contact surface 25 of the leg portion 21a. The groove 27 may extend radially from the center of the contact surface 25.

  According to this configuration, when the leg portion of the lens 21 is pressed against the substrate 22, the adhesive 24 can easily flow along the groove portion 27 to the side of the leg portion.

(Embodiment 4)
In Embodiment 1, the contact surface 25 of each leg of the lens 21 is circular, but the shape of the contact surface 25 is not limited to a circle. FIG. 9A is a front view of a leg portion 21a according to the fourth embodiment. FIG. 9B is a right side view of the leg portion 21a according to Embodiment 4. FIG. 9C is a perspective view of the leg 21a. The shape of the leg portions 21b to 21d is the same.

  As shown in these drawings, the leg 21a has an elongated elliptical shape and is curved so as to be convex when viewed from the front.

  In such a configuration, when the leg portion 21a of the lens 21 is pressed against the substrate 22, the adhesive 24 can be easily poured in the left-right direction when the leg portion 21a is viewed from the front as shown in FIG. 9A. Can do.

  In addition, as shown in FIG. 10, the side surface 26 of the leg part 21a may have an uneven | corrugated shape. Specifically, the side surface 26 may be textured.

  The display device according to the embodiment of the present invention has been described above, but the present invention is not limited to this embodiment.

  The above embodiment and the above modification examples may be combined. For example, the side surface of the leg portion 21a according to the third embodiment shown in FIG.

  The present invention can be applied as a display device to, for example, a television receiver that reproduces or records a television broadcast.

DESCRIPTION OF SYMBOLS 10 Liquid crystal display 11 Front cabinet 12 Bezel 13 Liquid crystal cell 14 Cell guide 15 Optical sheet 16 Reflective sheet 17 Rear frame 18 Case 19 Backlight unit 20 LED bar 21 Lens 21a-21d Leg part 21m, 21n Optical axis 22 Substrate 23 LED
24 Adhesive 25 Contact surface 26 Side surface 27 Groove portion 28 LED unit

Claims (7)

A substrate on which an LED (Light Emitting Diode) is mounted;
A lens that is arranged opposite to the LED and that widens the light distribution angle of the light emitted from the LED,
The lens includes a plurality of legs that are bonded to the substrate by an adhesive, and a contact surface of each leg with the substrate is curved in a generally convex shape. The lighting device according to claim 1, wherein a shape of the contact surface of each leg is a spherical crown shape. The lighting device according to claim 1, wherein the contact surface of each leg has a groove. The lighting device according to claim 3, wherein the contact surface of each leg has the groove extending radially from a central portion of the contact surface. The lighting device according to any one of claims 1 to 4, wherein a shape of a side surface of each leg portion is an uneven shape. The lighting device according to claim 5, wherein a side surface of each leg portion is subjected to a textured process. A display panel;
A display device comprising: the illumination device according to claim 1, which irradiates light to the display panel.

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